There must be a marine casualty happened every 4 days before 1984 , the amount of marine casualty happened at this area corresponds to 1 / 7 amount of the whole changjiang " marine casualty , so mariners gave it a name as " mouth of tiger " . due to the specific geographical condition and the extremely representative vessel traffic management of changjiang yingongzhou channel section , many intelligent people began researching and practicing the vessel traffic management of this changjiang " s down - stream complicated channel section from 1980s , at dec 15th 1984 the authority at that time - changjiang yingongzhou channel section previously ; up to the last years of 1980s ministry management administration applied traffic control on changjiang yingongzhou channel section previously , up to the last years of 1980s ministry of communications assigned shanghai marine college , shanghai ship & shipping research institute and changjiang harbor superintendence administration to make feasibility demonstrate about modern vts of zhenjiang traffic control section ; in 1990 dasha radar station which is the first radar vts station with inner river was finished , groped a new way for applying modern radar traffic control of vessel traffic management ; in 1997 the vtms of changjiang " s down - stream from nanjing to liuhekou was completed with connecting net and came into operation formally , meanwhile the signals of dasha radar station were conveyed to vts center by light cable , and then united applying vessel traffic management upon the whole authorized area ; in jun 2001 jiangsu msa made changjiang yingongzhou channel section as the first experimental group of creating " civilized , safe , passable channel activity , updating dasha radar antenna and receive - transmitter building closed - circuit television monitor system , setting uo safety warning board , starting navigational route reformation , carrying out united construction 1984以前这里平均每四天就发生一起海损事故，事故数占整个长江的1 7 ，被行船人称为“老虎口” 。长江尹公洲航段缘其极为特殊的地理区位条件和极具代表性的船舶交通管理，从上个世纪八十年代初就有识之士开始了这个长江下游最复杂航段的船舶交通管理探索和实践。 1984年11月15日当时的长江航政管理局在长江尹公洲水域率先施行交通管制；到八十年代末交通部委托上海海运学院、上海船舶研究所和长江港监局联合开展镇江交通管制段建立现代化交管系统的可行性论证； 1990年大沙雷达站? ?内河第一座雷达交管站建成，摸索实施现代化雷达交管的船舶交通管理新途径； 1997年长江下游南京至浏河口船舶交通管理系统建成联网投入正式运行，同时将大沙交管雷达信号通过光缆传输至交管中心，统一实施全辖区船舶交通管理； 2001年6月江苏海事局将长江尹公洲航段作为第一批创建“文明平安畅通航段”活动试点航段，更新大沙雷达天线和收发机，着手闭路工业电视监控系统建设，设立安全警示牌，启动航路改革，开展联合“共建” 。
By adjusting many variable geometry components of the engine , bypass ratio can be changed during large range ( the most 0 . 25 of military fighter ) . the high specific thrust characteristic of turbojet engine and the low specific fuel consumption characteristic of the turbofan engine can be realized during different flight phase by the usage of vce technology 变几何变循环发动机是应用于第四代多用途战斗机的理想动力装置，通过多个部件几何的调节在较大范围内改变涵道比，能够使发动机在不同航段分别实现涡喷发动机的高单位推力性能和涡扇发动机的低油耗性能。
